Configure

Open the config/feeds.js in your favorite text editor, and fill in the feeds.
Here is an example of configuration.

exports.feeds = {
'first': { // Each feed needs to have an unique key. It's is important as it will be used in the permalink for your feeds.
secret:'this is the secret for my first agregate', // Optional but you should put a random sentence here to make things secure.
name:"My very first agregate feed", // Name of your agregate feed
sources: [
"http://push-pub.appspot.com/feed",
"http://techcrunch.com/feed/",
"http://feeds.feedburner.com/ommalik",
"http://feeds2.feedburner.com/thenextweb",
"http://pandodaily.com/feed",
"http://news.ycombinator.com/rss"
] // this is the list of the feeds you want to agregate in one.
},
// ... Put more feeds here
}

The exported feeds object contains all the aggregate feeds you want to build with the sources to be used for each of them.

Profit

Once deployed, you should be good to start playing! yay!.
Now, a little warning: this aggregator will only agregate future entries, which means, that right when you're going to try it, there won't be much in there.

As you've configured your feeds in the first step, you can now access the aggregates in your browser. Each of them has 3 views: atom, json and html.
The base url to access them is http://APP_HOST/<key>/format (except for html, where you can just type http://APP_HOST/<key>/). The APP_HOST is your app's hostname and the <key> is the key you've chosen in the config/feeds.js file.

TODO

Use https to subscribe

Implement signatures to verify origin of content (we can use a secret set in the heroku:config for example.)

Add filters that can be applied to a feed, in the form of function called on each entry.

Make sure the generated feeds are PubSubHubbub enabled as well

Allow for an XMPP retrieval if an XMPP server is provided to connect to